Fluid-pressure controlling and reversing mechanism for grinding machines and the like



May 1929- A. P. BURNS FLUID PRESSURE CONTROLLING AND REVERSING MECHANISM FOR GRINDING MACHINES AND THE LIKE Filed April 18, 1925 a; IQ/F) $4 '& Em j May 28', 1929. p BURNS 1,714,545

- FLUID PRESSURE CONTROLLING AND REVERSING MECHANISM FOR GRINDING MACHINES AND THE LIKE Filed'April 18, 1925 4 Sheets-Sheet 2 19 f f Barres May 28, 1929. A. P. BURNS 1,714,545

FLUID PRESSURE CONTROLLING AND REVERSING MECHANISM FOR GRINDING MACHINESAND THE LIKE Filed April 18, 1925 4 Sheets-Sheet 5 May 28, 1929. A, p BURNS 1,714,545

FLUID PRESSURE CONTROLLING AND REVERSING MECHANISM FOR GRINDING MACHINES AND THE LIKE Filed April 18, 1925 4 SheetsSheet 4 atented May 28,

AIiFRED E. BURNS, OF WOBGESTEB, MAS

GEINE CQMPANY, 0F WORCESTER, SACHUSETTS, A130 (ERECTION 0E a OHUSE'KTQ, ASSIGNOR TQ TE H1) EA- rnnrn-ranssn oonraonnrne'nnn nnvngasme mncnrsn' non dnrnnme m- 7 V "IRES AND ran at. I

Application filed April 18,-, was. a semi mi. seam.

The present invention relates to fluid pressure mechanism for controlling and reyerslng the movements of reciprocator machine elements, as being here shown an described, by way of example, in operative relation to the reciprocatory tables of internal grinding machinery. The invention mvolves certa n modifications in the construction and opera-- tion of the fluid pressure controlling and reversing mechanism which is, shown and described in the copending applicatlon of Heald and Guild, Serial No. 639,882, filed April 4, 1923, now Patent No. 1,582,468," granted April 27, 1926, by way of adapting the principlcs and capabilities of that mechanism to the operation of a plurality of independent reciprocating machine elements, all actuated by a single source of fluid pressure supply, and embodied either in the same or in difierent pieces of machinery. The-features of the invention are fully set forth hereinafter, reference being had to theaccompanying drawings, wherein Fig. l is a view of the interior of a grinding machine, that isto say with the front part of the frame casting removed, certain partsm said interior being shown in section,-said figure also indicating so much of the mech-- anism of an internal grinding machine exte-; rior to said frame casting asis'necessary for the proper disclosure of my invention.

Figs. 2 and 3 are fragmentary detail views, partly in section, showing the valve mecha nism of'Fig. 1 in different positions, the bypass valve for convenience being omitted.

Fig. 4 is a view similar to Fig. 1, showing a modified form of the invention in relation to a different arrangement of the grinding machine instrumentaiities. p

Figs. 5 and 6 are fragmentary detail views, partly insection, showing the valve mechanism of Fig. 4 in diiferent positions, the by pass valve for convenience being omitted.

Fig. 7 is an enlarged detail view, partly in section, of one of the valve devices.

Fig. 8 is a fragmentary front elevation of .the grinding machine of Fig. 1, showing the mechanical elements of the reversing mech-' anism.

Fig. 9 is a fragmentary view of one of the Fig. 10 is a view of a portion ofthe mech-f f anism shown in Fi 8, with the front portion of the casing for t e reversing levers broken away to show the connections.

Like reference characters in the difl'erent figures.

Referring first to Fig. 1, there is shown a refer to like parts fluid pressure cylinder 1, the latter containing the usual double-acting piston 2, which is suitably connected, as by a rod 3, with the element-4 to be reciprocated, here shown as the table or carriage of an internal grinding machine. grinding wheel or the work to be ground may be carried by the table 4, the reciprocations of the latter being utilized in either case to produce a relative traversing movement between the grinding wheel and the work..- As here shown, the table 4: supports and carries the usual grinding wheel head 5, the work supporting head 6 being carried by a bridge 7 which spans the slideways of the machine frame in which the table 4 moves.

For the back and forth movement of table 4, fluid under pressure is admitted to one end or the other of cylinder 1, and for this purpose, the machine here shown is equipped controlling systems for a variety of movable machine elements; that is, .in additionto the branch supply pipe 10, through which fluid under pressure is conveyed from the main 8 to the actuating and controlling de vices of table 1, there may be connected to the main 8 additional branch supply pipes such In such a machine, either the as 10., for the conveyance of pressure medium to another system or systems, not shown,

employed, for'example, for theactuation and control of another element of the same machine, or the table of another grinding machine, or the tables of a battery of grinding machines. A detailed description'of these additional systems andmachines is unnecesfree addition, a return pipe 12, corresponding tothe return pi e 12 of the systemshown, which connects'witli the exhaust main 9. In each such system, if em loyed for the actuation of a reciprocating ta le, pipe connections, corresponding to the pipe connections 13 and 14 from the reversing valvell to the opposite ends of the cylinder 1, would be provided,

7 and the operation of all these systems, having the common supply and exhaust mains 8 an 9' would be, as hereinafter described, for the single system illustrated in Fig.1.

In such system, the various'valve'devices for controlling the pressure fluid are disposed in a suitable block or casting 15, which provides a passage 16 to the reversing valve 11- from the branch supply pipe 10. Said-passage 16 is provided with a rotatable plug or throttle valve',17, the position of which is subject to adjustment to vary thequantity of pressure fluid flowing through the passage 16, and hence the speed at which the table 4 is reciprocated. The reversing valve 11 may be of the form and construction shown for the reversing valve in the aforesaid copending application, or itmay be of the simplificd form of constructionshown diagram; matically herein; in any event,it will be understood that when said valve is oscillated in a counterclockwise direction from its central or neutral position, communication is established, as shown in Fig. 1, between passage 16 and a port or passage 18, the latter communicating with the pipe 13 that leads to the left hand end of cylinder 1. At the same time, this position of the valve 11 also establishes communication between the re-- 1 turn pipe 12 and the pipe 14, leading from the right hand end of cylinder 1, so that when the pressure of the fluid is exerted against the piston 2 to drive it to the right, the fluid on the right hand side of said piston has a free and unthrottled passage back to the exhaust main 9 and to the tank, not shown,

through the pipes 14 and 12 and the valve 11. Inthe opposite positionof said valve,

these conditions are reversed, the pipe 14 be-- ing connected. to the passage 16, so that thepressure' of the fluid is exerted against the right hand side of the piston to drive it to the left, while the fluid on the left hand side of said piston has a free and unthrottled passage back to the exhaust main 9 through pipe '13, passage 18, valve 11 and'return pipe 12. a The movements of said Valve 11 may be efi'ected in the usual or any desired manner byspaced adjustable dogs or stops 43 and44, Fig. 8

on table 4. The table dogs or stops 43 and 44 are usually spaced apart a distance substantially corresponding to the desired working stroke of the grinding wheel, being alter- (1 tion oftravel of the table.

natel'" brought into action to efi'ect the re-. versa of an interposed member 45 at the end of each traverse of the table 4 in one direcniember 45 is, consequently, transmitted to the reversing valve 11 to controlthe direc- When the member" 45 is struck by on'e'of the dogs 43 or' 44, it-is rocked on its axis 46, and the-initial movement thereof thus inaugurated is continued by the action of a s ring 50 which maintains the ointed end 0? a cam lever 51 in contact wit the flat angular sides of a projection 52o'n the rear of the member 45, this constituting, of course, merely a particular form of snap over device. 4

In the use of an internal. grinding ma chine such as here shown, there is frequent necessity for interrupting the grinding operation in order that the'o erator may size or plug the hole which is 'eing ground; such action by the operator, and also the removal of work .from the machine and the introduction of a new piece of work, requires the wheel and the work to be separated axially or longitudinally, in order to give access to said work. In the machine herein illustrated, this separation is obtained by causing the movement of the table 4 to the extreme right, to carry the grinding Wheel away from its normal reciprocatory working path; for this purpose, as shown in the aforesaid copending application of Heald and Gui1d,the left hand table dog 43 is rendered inoperative, in-any suitable-manner, with respect to the reversing valve 11 as by the provision of a pivotal mounting 53 for the dog 43, said dog normally hanging by gravity in the position shown in Fig. 8, and being held in that posi tion by a blo ck. or projection 54 whichthus' supports the dog. When the striking endoi. the dog43 is lifted in any manner, it is raised above the topof the reversingmember 45, so that the reversing valve 11, instead of being rocked clockwise into its other position at the end of the normal ri ht hand working stroke of the table 4, remains in the position illustrated in Fig. 1. This prevents any interruption to the passage of pressure fluid to the left hand end of cylinder 1 and results, therefore, in an amplified right hand movement of table 4, such movement, as described -in the aforesaid copending application of ing valve 11. Osc1llat1on of the reversing arrests maintain in a valve 19 in open position, thus permitting the pressure fluid to by-pass the throttle valve 17. During the normal working reciprocations of table 4, the valve 19 is maintained in contact with its seat by a spring 20, thus keeping the by-pass 2O closed. I

In order to facilitate the elevation of pivoted table dog 43 in the act of causing the grinding wheel to be withdrawn from ts working zone, the-construction shown in Flg.

9 may be adopted in lieu of or in addition to a pin or handle 56 projecting from said dog.

As shown in Fig. 9, a lever arm,57, pivoted at '58 to the frame of the machine, provides a rising cam surface 59 at the left hand side of the projecting upper end of reversing member 45. Said'lever 57 in its normal, or moperative position, as indicated in full lines in Fig. 9, rests by gravity against a pin or stop 60, said pin projecting from the frame into an enlarged hole or recess 61 of said lever. The loose fit of pin 60 in the hole 61 allows the lever 57 to be lifted into the dotted line position of Fig. 9 when seized by its project ing handle'62, thereby bringing cam 59 into the path of pivoted dog 43 so that, onthe right hand movement of the table, said dog will ride upwardlyonsaid cam surface and justclear the upper end of reversing member 45. In this way the operator, in the act of causing said dog to pass inoperatively over the interposed upper end of the reversing member 45, is relieved of the necessity of seizing hold of a moving member, i. e., the dog itself, and

' is enabled to effect the desired result by elevation of a member which undergoes no change of position along the frame of the machine.

According to the present invention, the port or passage 18, which connects the reversing valve 11 with the left hand end of cylinder 1,

is subject to the action of a valve 21, which is loosely and slidably mounted on a stem 22, said stem projecting outwardly through the block 15 and being pivotally connected at 23 to a lever 24. Said lever 24, which is pivoted on a fixed axis 25, carries at..its free end a roller 26 which, all during the normal working travel of the table and also during the right hand withdrawal movement of said table, rides against the horizontal under surface of an elongated cam bar 27,-carried by said table. A compression spring 28, act- 1ng on lever 24, continuously exerts its force to thrust said lever upwardly, but the contact of roller 26 with cam bar 27 prevents such upward movement, and thus the'valve stem 22 is maintained in the depressed position shown in Fig. 1, wherein, notwithstanding the ability of valve 21 to slide on said stem, said valve is prevented-from seating in or closing the passage 18, lay-reason of the stem reaching the bottom ofthe valve recess 29, best shown in Fig. 7. In other words, so

long as the roller 26 rides against the extended horizontal surface of the cam bar 27, the stem 22 acts as a positive abutment against the closure of valve 21, and this notwithstanding the fact that said valve is at all times subject to the action of a spring 30, lighter than the spring 28, tending to move it into closed position.

The cam bar 27 terminates at its left hand end inan upwardly inclined section 31, and when this inclined section 31 arrives above the roller 26, it marks the end of the right hand withdrawal movement of the table 4. The spring 28 forces the roller 26 up said incline, as shown in Fig. 2, and this action raises the stem 22 and allows the Valve {21 to close under the action of the light spring 30 and also by the pressure of the fluid on the under side of said valve. This closure of the valve '21 shuts off the supply of pressure fluid to the left hand end of cylinder 1, and thus brings the table 4 to rest. However, the arrangesure normally maintained on the fluid for the operation of such systems. The arrangement thus distinguishes from that shown in the aforesaid application of Heald and Guild, where the stoppage of the table in its fully withdrawn position involves a free circulation of the pressure fluid through the system 1 and a consequent drop in the pressure of said fluid. The closure of valve 21-as above de-- scribed locks the pressure fluid in the left hand end of cylinder 1 and prevents any movement of table 4 until the reversing valve 11 is swung clockwise by hand into its other position, as shown in Fig. 3. This action opens the right hand end of the cylinder to pressure through branch .pipe 10, by-pass 20, and pipe 14, and inaugurates the return movement of the table at high speed. The fluid locked in the left hand end of the cylinder 1 is thus put under suficient pressure to open the valve 21 against the force of light spring 30, and'said fluid makes its return to the tank 11 by way of passage 18, valve 11, return pipe 12 and exhaust main 9. Upon the completion of the high speed return movement of table 4, said table automatically'resumes its normal working reciprocations at a speed dc- 1Z9 termined by the setting of throttle valveli.

Referring now to Fig. 4, the invention is shownin connection with a single grinding machine having two separate independent reciprocatory elements, namely the tables 32 and 32', carrying the grinding wheels 33 and 33 respectively, for operation, simuiltane ously or otherwise, within the opposite ends of a single rotary work piece 34. Each table has associated therewith a fluid pressure sys- 1 .0

-Figs. 4, 5 and 6 is as follows In the normal operation of the machine, and 3, the valve 21 and its associated mech'atem similar to the system disclosed in Fig. 1, or 27' this being due to the abutment prothe two systems being connected to a comvided by the lower end of the stem 22 or 22'. mon pressure supply main 35-and to a com- Assumlng that both grmdmg wheels 33 and mon exhaust main 36, the latter having a re- 33' are operating, as ab ove described, 1 f now turn pipe 37 to a tank 38, and the former being it be desired to dlscontmue the operation of supplied by. a pump 39 for the circulation, one of them, say the wheel 33, without inter-- under pressure, of the fluid from said tank. rupting the operation of the other, the left Saidpump 39 provides also a relief valve conhand table dog, not shown, for the reversing nection 40 to the pipe 37 v valve 11, is rendered inoperative, so that said The two systems shown in Fig. 4 involve valve, instead of being rocked clockwise into the same mode of operationand the same eleits other position at the end of the normal ments as the system shown in Fig. 1, except right hand working stroke of table 32, refor the fact that the valve which is brought mains in theposition illustrated in Fig. 4.

into action when the table reaches the end This prevents any interruption to the-pas- Q of its withdrawal movement, is differently sage of pressure fluid through passage 41 and situated from the valve 21 of Figs. 1,2 and 3. connection 13 to the left hand end of cylin- I Referring to Fig. 4, the supply main 35 proder 1, and results therefore in an amplified vides branches 10 and 10. running to reversright hand movement of table 32, such moveing valves 11 and 11', and from the casings of ment, as he'r'etdfore described, these valves, return pipes 12 and 12' connect taking place at maximum speed, us to the with the exhaust main 36. The respective opening of the associated by-pass valve 19.

systems provide the pipe connections 13, 13 This amplified right hand movement finally and 14, 14 to opposite ends of the cylinders brings the inclined section 31 of cam bar 27 1 and 1, the connections 13 and 13' corre-' above the roller 26, whereupon the spring 28 I sponding to the connection 13 of Fig. 1, and raisesthe lever 24 and stem 22, as-shown in providing for the flow of pressure fluid from Fig. 5, allowing the valve 21 to close the pasthe valve casing to the cylinder when the sage 42 under the action of spring 30, and also movement of the piston in said cylinder is to by the pressure of the fluid on the under side carry the associated grinding wheel 33 or of said valve. Thus, notwithstanding the 33 away from the work piece 34. The conmaintenance of full pressure in the left hand nections 14 and 14, like-the connection 14' of end of cylinder 1, the table 32 is brought to Fig. 1, provide for the flow of pressure fluid rest, because the outlet of pressure fluid from from Valve to cylinder when the associated the right hand end of said cylinder is shut off; grinding wheel 33 or 33 is to be carried it will be seen therefore that this stoppage of toward the work piece 34. table 32, in the manner above described, does In the present instance however, as distin-' not in any way affect the continuing working guished from the arrangement shown in Fig. reciprocation of the table 32', notwithstand- 1. the connections 13 and 13 communicate ring the fact that said two tables have a comdirectly with their reversing valve recesses mon source of .flui'd' pressure actuation.

by means of passages 41 and 41, these lastlWhen it is desired to have the grinding wheel named passages, unlike the passage 18 of 33 resume operation, the reversing valve 11 is Figs. 1, 2 and 3, being at all times open and swung from the position shown in Fig. 5 to having no valves whatsoever therein. On the position shown in Fig. 6; this action the other hand, the passages 42 and 42, which brings the full pressure of the fluid directly on afford communication between the pipe conthe upper side of valve .21, thereby opening ncctions 14 and 14' and their respective valve said valve and inaugurating the return or recesses, are supplied with valves 21 and 21, left hand movement of the table 32 at high of the same construction and mode of operaspeed. I

tion as the valve 21 of Figs. 1, 2 and 3, and the It will thus be seen that each form of the operation of this mechanism, referring to invention herein disclosed obtains the same result, the difference being that in Figs. 1, 2

either one or both of the grinding wheels 33 nism is disposed, forthe withdrawal stroke of and 33 may be making the usual reciprocatable 1, on the pressure side of reversing valve tory traverse within the work piece 34, the re-- 11, whereas said valves 21 and 21' in the arversals of thesemovements being effected by rangements shown in Figs. 4,5 and 6 are disthe table dogs or stops, not shown, but which posed, for the withdrawal strokes of tables and 44, which alternately throw the valves of the valves 11 and 11, respectively. How- 11 andll to the right and to the left. Under ever, regardless of whether the action takes these conditions, when either grinding wheel place in the pressure line to one end of the is working, its associated valve 21 or 21' is cylinder, or in the exhaust line from the other held in open position by the engagement of end, the results accomplished are one'and the roller 26 or 26', as the case may be, with the same. The main object of this invention is extended horizontal surface of the cam bar 27 to stop the flow of fluid under pressure in may be substantially the same as the dogs 43 32 and 32, respectively, on the exhaust side one direction only without affecting the free passage of the pressure fluid in the opposite direction at the will of the operator, by the natural and accustomed movement of reversing the valve 11. The invention of the aforesaid copending application accomplishes this purpose, but with the loss of pressure-in the supply line, while in the apparatus of the present invention, the pressure is retained. it is obvious that other modifications ma be made without departing from the spirit oi the invention, the scope whereof is set forth in the following claims.

I claim:

.1. In apparatus of the class described a table, fluid pressure meansfor reciprocating said table, a reversing valve for the pressure fluid operated by said table at each end of the latters normal working path, means operable at will to prevent a reversal of said valve, thereby to procure the withdrawal of said table, by fluid pressure actuation, from said working path, a normally open valve independent of said reversing valve, and means adapted to close said valve when the table reaches a predetermined point in its said withdrawal movement, whereby to discontinue the flow of pressure fluid to bring said table to rest.

2. In apparatus of the class described, a

table, fluid pressure means for reciprocating.

said table, a reversing valve for the pressure fluid normally operatedby said table at each end of the latters predetermined working path, means operable at will to prevent a re versal of said valve, thereby obtaining the withdrawal of said table by fluid pressure ac tuation from said working path, and means for automatically. bringing said table to rest at a predetermined distance from said working path, said means comprisingan independent valve for discontinuing the further flow of pressure fluid through any part of said reversing valve.

3. In apparatus of the class described, a

table, fluid pressure means for reciprocating said table, a reversing valve for the pressure fluid normally operated by said table at each end of the latters predetermined working path, means operable at will to prevent a reversal of said valve, thereby obtaining the withdrawal of said table by fluid pressure actuation from said working path, and means -for automatically bringing said table to rest at a predetermined distance from said workmg path, sald means, comprlsmg a valve,

closed in part by the pressure of the actuating table, a piston and cylinder unit adapted, by

fluid pressure actuation, to reciprocate said table, a reversing valve for the pressure fluid operated by said table at each end of the latters normal working path, said valve having a port leading to each end of said piston and cylinder unit, means operable at will to prevent a reversal of said valve, thereby to procure the withdrawal of said table, by fluid pressure actuation, from said working path, a normally open valve independent of said reversing valve, located between that end of the piston and cylinder unit to which fluid is flowing to cause said withdrawal movement and the port in the reversing valve by which the fluid is led thereto, and means adapted toclose said independent valve when the table reaches a predetermined point in its said withdrawal movement, whereby to discontinue the flow of pressure fluid-to bring said table to rest. Dated April 14, 1925.

ALFRED P. BURNS. 

